Oracle is making a fresh run at Microsoft's SQL Server, claiming on Tuesday that its open-source MySQL database offers up to 90 percent cost savings over SQL Server along with blazing performance on Windows.

An online event is scheduled for Wednesday. During the event, Oracle intends to outline why MySQL is a compelling option for use on Windows, both by software vendors and enterprises. It will also discuss "upcoming milestones [that will] make MySQL even better on the Microsoft platform," and how to deliver "highly available business critical Windows-based MySQL applications."

MySQL user SonicWall, a security vendor, is also slated to discuss why it chose the database over SQL Server, according to a statement.

In addition, Oracle announced an upgrade to MySQL Enterprise Edition that adds capabilities for "hot" online backups; new graphs for visually monitoring systems; a number of data modeling and administration tools and integration with Oracle's support portal.

This is far from the first time MySQL has been positioned against SQL Server, as its former owner, Sun Microsystems, made similar moves for years. A Microsoft spokesperson could not immediately provide comment Tuesday.

Oracle's announcements show it is eager to diminish any lingering perceptions that MySQL, which it acquired through the purchase of Sun Microsystems, is strictly the province of Web companies and startups. At the same time, it wants to retain MySQL's image as a lower-cost alternative to databases like SQL Server.

But the company's competitors have room to quibble over exactly how much lower-cost MySQL is.

The MySQL website features a chart that details Oracle's TCO (total cost of ownership) claims, comparing the cost of a MySQL subscription to licenses and maintenance charges for SQL Server as well as Sybase ASE. However, the figures used do not take into account the ample discounts vendors typically negotiate with customers on license fees.

In addition, the MySQL subscription fee used -- US$5,000 annually -- is for servers with one to four sockets. That cost doubles for servers with five or more sockets, according to Oracle's official MySQL price list.

As Oracle places SQL Server in its sights, it is also facing growing competition for MySQL revenue from startups like SkySQL, which independently offer support services for the database.

Overall, Oracle's marketing and development efforts behind MySQL come as no surprise, one observer said.

"Given how hard Oracle fought against the antitrust authorities to keep MySQL around the time of the [Sun] acquisition, we always knew they were serious about the business," said analyst Curt Monash of Monash Research.

Oracle will show it is even more serious if it buys technologies that enhance MySQL, such as the open-source analytic data warehouse Infobright, Monash said. Sun was an investor in Infobright, which has already been integrated with MySQL.

Still, no matter what Oracle does, expectations should be tempered for MySQL's success against the SQL Server installed base, according to Monash.

"Oracle-quality MySQL's most obvious target is SQL Server," he said. "But if you have bought into the Windows stack, why not stay bought-in? The competition is mainly about new applications. Few users will actually switch."

However, "a lot of SaaS vendors use Oracle Standard Edition, and have some MySQL somewhere as well. They don't want to pay up for [Oracle] Enterprise Edition or Exadata. Good MySQL could suit them," Monash added.

But even with the improvements to MySQL Enterprise, there are still large gaps between its feature set and that of Oracle's flagship database. The latter remains superior in areas like security, datatype support and analytics, Monash said.